First Missing positive in a range

Revision en1, by tanmaydatta, 2017-05-14 19:39:50

I recently gave a hiring test and was stuck on a particular problem. The problem is as follows:

You are given an array A of N elements and Q queries of the form L,R.

For every query find the first missing positive integer in the range A[L],A[L+1],A[L+2] ...... A[R].

N <= 10^6

Q <= 10^6

1<= A[i] <= 10^9

I know how to find the first missing positive in O(N) but don't know how to handle multiple queries in less time. Any help would be appreciated. Thanks


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en1 English tanmaydatta 2017-05-14 19:39:50 509 Initial revision (published)